Genomic DNA was extracted from three pedigrees of manic depressive and schizophrenic patients. Similarly, DNA was obtained from a panel of unrelated patients and control individuals. One Family with manic depressive illness was informative using the restriction fragment length polymorphisms (RLFP's) in the somatostatin gene. Linkage analysis was performed on this pedigree under several modes of inheritance. The lod scores were negative, thus close linkage of the somatostatin region to the disease locus is unlikely. No apparent association was found with this gene. Allmanic-depressive families were informative using the insulin probe. Examination of the insulin gene data for linkage awaits blotting of completed pedigrees. Novel RFLP's were discovered using complement C4, neuropeptide Y and the Beta-hexosaminidase Alpha-chain as cDNA probes. Initial results with neuropeptide Y revealed the presence of an RFLP allele in the DNA of several manic-depressive and schizophrenic patients but not in any normal individuals. Calmodulin-specific cDNA clones were isolated from a rat brain Lamda gt11-cDNA library using calmodulin cDNA from Xenopus laevis.